Angle setting control for drafting instruments



March 11, 1958 E. J. HUFF 2,825,971

ANGLE SETTING CONTROL FOR DRAFTING INSTRUMENTS Filed Jan. 28, 1954 2 Sheets-Sheet 1 EMERSON J. HUFF INVENTOR.

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HIS ATTORNEY March 11, 1958 v E. J. HUFF 2,825,971

ANGLE SETTING CONTROL FOR DRAFTING INSTRUMENTS Filed Jan. 28, 1954 2 Sheets-Sheet 2 IN V EN TOR.

BY CE. W

ms ATTORNEY EMERSON J. HUFF United States Patent Office 2,825,971 Patented Mar. 11, 1958 ANGLE. SETTING CONTROL- FOR- DRAFTING INSTRUMENTS Emerson J; Huff, Pomona, Calif.

ApplicationJanuary 28; 1954, SerialNo. 406,714

4Clain1's. (Cl. 33-79) 'Ihi'sinvention relates to an angle setting control for drafting instruments.

The orientable heads of certain conventional drafting instruments such as the Bruning are provided witha ring which is connected'to the moveable arms of the instrument' and on which is rotatably mounted a 'sup'portto which the draftinginstruments are attached; The drafts man can move the ring to any desired position on the drafting boardby means of a control knob; The support is normally locked in position so that one arm'of the drafting instruments is in horizontal position, parallel to" the base of the drafting board and the other'arm is perpendicular thereto; An automatically acting bolt is provided which enables the support tobe locked'in'other predetermined positions, which are customarily 'everyfifteendegreesoff'ffrom horizontal. Itis also possible for the draftsm'a'n" to change the basic angle from horizontal to'anydesired angi'e'a'nd work'with tift'een'deg'r'ee v'aria ti'ons' therefrom. I

If, however, the draftsman desires to use any angle otherthan the basic angle for which the instrument is set or a fifteen degree: variation therefrom, it is necessary for'hirn to set suchiangle by the use of. the protractor. If theangle' is left to work at'another angle, itmus't'be re-setby visual reference to the protractor. In practice; itis 'diflicult if not impossible for the draftsman to make precisely the same .setting the second time that he made" the first time. In such case, the angle issligh'tly different and the drawing is sligthly off from theprevious" angle, resulting" in inaccuracy in the drawing; 7

It is an object of my invention to provide anarfgl'e setting control which will permit the draftsma'n' to" set the'arms' for any angle whatsoeverwith respe'ctto the basica'ngle; He can then leave the set'angle 'tdmove' to'the basic angle or to any other angle and at any later time return to the set angle, with my controlproviding precisely the same set angle as that previously used.

It is a further object of my invention to provide such a:- control which will not interfere in any way" with the' other" operations of. the drafting instrument, but'which will. provide the? aforesaid advantages and benefitsin addition to those already provided by the instrument.

Myinvention also comprises such other objects, advantages and capabilities as will later morefully appear and-which are inherently. possessed by my invention.

While I have shown in the accompanying drawings" and described herein. a preferred embodiment of my invert; ti'o'n', it should be understood thatthe'same is susceptible of modification and change'w'ithout" departing fron'rthe spirit'of myinvention.

Referring to the drawings, Fig. 1 isa" top plan view of'my device with the brake in unlocked position;

'Fig'. 2 is a top plan view of the brake,.showing'the same in l'o'ckedfposition;

Fig. 3 is" a" side elevational view of my device;

Fig. 4isatopplan' view of another embodiment of my b'rake; H I

Fig. S'is'an end elevati'onal viewot the-same;

Fig; 6 is a reduced top plan view of my device in use, showing the drafting instrument in dotted lines;

Fig. 7* is a perspective view of my device.

A preferred embodimentwhichhas been selected to illustrate my invention comprises an angle setting ring 10, which is rotatably mounted on the non-rotating part ofthehead' of the d'rafting'machine; Ringjl ll is'formed of two semicircular members 11 and 12, which are'joined together at one end by a hinge link 13, so that ring 10 may be opened for attachment to the drafting. instrument. The" opposite ends of members 11 and 12 are fastened together bya set screw 14, which extends through screw threaded openings in flanges adjacent the" ends of members 11 and 12 to hold ring, 10' in place on the drafting, instrument. p

A spring loaded trigger and release assembly'is' provided'on member 11 of ring 10. Such assembly comprises a substantially triangular trigger 15, which extends outwardly from ring: 10 to provide" a substantially right angle stop portionl. Positioned adjacent the outer circumference'of' ring 10' is a small hook portion 17 which is integral-with" trigger 15. Trigger 15 is pivotally attachedto ring10 biy'a pivot pin 18. A small wirespring 19 is positionedhetw'een trigger 15 and'ring 10 to bias trigger 15" in an outward direction from ring 10. A-pin 20'limits the outwardm'oveme'nt of trigger 15.

A 'springload e'd 'trigg'errelea'se 21 is pivotally, mounted on a pinzz'which' extends throughmember 11 of ring 10 adjacent triggerlSi Triggenrelease 21 is provided with a small catch portion 23, which is normally biased downwardly by a small w'ire spring'12'4;

The other'member 12 of ring 10is provided with a brake which is adapted'to' bear againstlthe head of the drafting movement and prevent the rotation of lringfllfll A brake sh'oe' 25 is formed from an integral elongated portion of member 12 and is slightly yiel dable. A lever 26 is'p'ivota'lly' mounted 'on'a pin 27 wl1ich extendsthrough memberl'z adjacentbrake sh'oe 2 5. Lever 26 has a finger portion 28 and an eccentric portion 291 When finger portion"28"is in its outward position, extendingat a right angle to ring 10' as shownin Fig. l of the drawing's, brake shoe 25 is concentric with'the. inner circumference ofring 10. This is'the released or unlocked positionto'f my brake; V

When finger portion 2'8 is in its inward posi tion, extending. alongside ring 10 as shownin Fig. 2 of the drawings, the side of eccentric portion'29 engagesbrake shoe.25l Because of the oval or eccentric shape of eccentric portion 29; the cigtance from pin 27 to the side of eccentric portion 29 is greater than the distance from pin 27 to the end of eccentric portion 29. In order to accommodate thelarger side of eccentric portion 29,1 brake shoe 25 is forced inwardly towardthe center of ring, 10; Brake shoe 25 thus bears againstthe head of the drafting instrument to prevent the rotation of ring 10 when the brake isin locked position.

A stop, is provided in the form of a knob 30 having a shaft 31 which projects upwardly into the path-of: trigger 15 when-- trigger 15 isin its outward positions The drafting instrument is provided with a hexagonal nut which is a part of the leveling adjustment of theiinstr'ument.- Thisnut is removed and replaced with-my kn'ob 30-toprovide a stop means for my'control device:

In use, all that need be done to install my deviceis to' replace the hexagonal nut with" my knob" 30 andattach ring 10"to the head of the instrument. Ring 10* pivots open on hinge link 13 and is fastened in place by the tightening of set screw 14'.

Iii orderto set my angle control to hold the particular angle" at which the drafting instrumentisi s'et, finger'pon $01128 of lever 26" is moved outwardly; releasing brake shoe 25 from bearing engagement with the head of the drafting instrument. Trigger release 21 is depressed so that its catch portion 23 is moved upwardly, freeing hook portion 17 of trigger 15 to permit trigger 15 to move to its outward position.

Ring 10 is then rotated in a counterclockwise direction until stop portion 16 of trigger 15 strikes against shaft 31 of knob 30, as shown in Figs. 1 and 7 of the drawings. This prevents any further rotation of ring 10. If ring 10 is rotated in a clockwise direction, it is moved until trigger 15 is depressed by cam action as it passes shaft 31. Trigger 15 is moved toward ring 10 short of engagement between catch portion 23 and hook portion 17 and snaps back with a clicking sound. When this occurs the direction of rotation is reversed to move the head in a counterclockwise direction until stop portion 16 of trigger 15 abuts against shaft 31.

The brake is then applied by moving finger portion 28 of lever 26 toward ring 10, bringing brake shoe 25 into engagement with the head of the drafting instrument. This prevents any further rotation of ring 10 with respect to the head of the drafting instrument.

When the draftsman is ready to leave the set angle temporarily, he presses trigger 15 toward ring 10 until hook portion 17 becomes engaged with catch portion 23 of trigger release 21. The head of the drafting instrument may then be moved to any angle desired.

When the draftsman desires to return to the angle for which my control has been set, he need only press trigger release 21 to release trigger 15 to its outward position. The head of the drafting instrument is then rotated in a counterclockwise direction until stop portion 16 of trigger 15 strikes shaft 31 of knob 30. If the head is moved in a clockwise direction, it is moved until trigger 15 clicks as it passes shaft 31 and the movement is then reversed until stop portion 16 contacts shaft 31. The head is then back at the exact original angle for which my control was set. The angle is precisely the same as that previously set and no resetting or measurement is necessary.

It may be noted that my device does not interfere in any way with the operation of the drafting instrument. Knob 30 merely replaces a locknut and does not effect the operation of the leveling adjustment. Member 12 of ring 10 is provided with a cutaway portion 32 to clear a ring nut which might interfere with ring 10 on some models of drafting instruments.

An alternative form of my brake is shown in Figs. 4 and of the drawings. In this embodiment, the same lever and pin construction are used, but in connection with a small link 33, which is attached by a pin 34 to a portionofm'ember 12 which is separated from the point of attachment of lever 26. When the finger portion 28 of lever 26 is positioned alongside ring 10, the brake is in unreleased or locked position. When the finger portion 28 is moved outwardly at a right angle, the diameter of ring is effectively expanded to release ring 10 and permit its rotation with respect to the head of the drafting instrument; This is accomplished by the movement of pin 27 upwardly toward the upper end of link 33, since the distance fromv pin 27 to the side of eccentric portion 29 is shorter than the distance from pin 27 to the top of eccentric portion 29.

It should also be understood that other suitable types of brake means may be employed.

1-. An angle setting control for drafting instruments of the type-having a rotatable head and a non-rotatable stop member disposed adjacent thereto, said control comprising a circular ring, said ring being formed of a pair of semi-circular members joined at one end by a hinged link and at the opposite end by disconnectable fastening means, a substantially triangular trigger member pivot ally attached to said ring, the outer surface of said trigger member being curved to provide a cam surface, spring means biasing said trigger member toward an outward position in which it projects beyond the outer circumfer'ential edge of said ring, said trigger member having a substantially right angle stop portion at one end of said cam surface, said trigger member having a catch portion, a trigger release pivotally attached to said ring adjacent said trigger member, said trigger release having a hook portion engageable with the catch portion of said trigger member, spring means acting on said trigger release to hold said hook and catch portions in engagement to prevent the movement of said trigger member to outward position, said trigger release being manually pivotable to release said hook in catch portions and permit movement of said trigger member to outward position, brake means carried by said ring, said brake means being manually movable to an operative and a non-operative position, said brake means in operative position contracting said ring into frictional engagement with the head of the drafting instrument to prevent rotation of said ring with respect thereto, said brake means in non-operative position expanding said ring to permit rotation thereof with respect to said head, the right angle stop portion of said trigger member acting when said trigger member is in outward position to engage the stop member on the drafting instrument and prevent rotation of the head in one direction, the cam surface of said trigger member engaging said stop member to move said trigger member inwardly against its spring means to permit rotation of the head in the opposite direction when said trigger mem: ber is in outward position, said trigger member when not in outward position being non-engageable with said stop member.

2. An angle setting control for drafting instruments of the type having a rotatable head and a non-rotatable stop member disposed adjacent thereto, said control comprising a circular ring, a trigger member attached to said ring, spring means biasing said trigger member toward an outward position in which it projects beyond the outer 1 circumferential edge of said ring, said trigger member having a catch portion, a trigger release pivotally attached to said ring adjacent said trigger member, said trigger release having a hook portion engageable with the catch portion of said trigger member, spring means acting on said trigger release to hold said hook and catch portions in engagement to prevent the movement of said trigger member to outward position, said trigger release being manually pivotable to release said hook and catch portions and permit movement of said trigger member to outward position, brake means carried by said ring, said brake means being manually movable to an operative and. a non-operative position, said brake means in operative position contracting said ring into frictional engagement with the head of the drafting instrument to prevent rotation of said ring with respect thereto, said brake means in non-operative position expanding said ring to permit its rotation with respect to said head, said trigger mem-' ber acting when in outward position to engage the stop member on the drafting instrument and prevent rotation of the head, said trigger member when not in outward position being non-engageable with said stop member.

3. An angle setting control for drafting instruments of the type having a rotatable head and a non-rotatable stop member disposed adjacent thereto, said control comprising a circular ring, a trigger member attached to said' ring, spring means biasing said trigger member toward an outward position in which it projects beyond the outer circumferential edge of said ring, manually operable means for holding said trigger member away from said 1 outward position against the pressure of said spring means, brake means carried by said ring for selectively permitting and preventing manual rotation of said ring with respect to the head of the drafting instrument at any, point on the circumference of said drafting instrument,

" said triggermember acting when in outward position to engage the stop member on the drafting instrument and prevent rotation of the head, said trigger member when not in outward position being non-engageable with said stop member.

4. The subject matter of claim 3, said brake means being manually movable to an operative and a non-operative position, said brake means in operative position contracting said ring into frictional engagement with the head of the drafting instrument to prevent rotation of said ring with respect thereto, said brake means in non-operative position expanding said ring to permit its rotation with respect to the head of the drafting instrument.

References Cited in the file of this patent UNITED STATES PATENTS 

